Mobilisation of radionuclides during uranium and gold processing of granitic rock at El-Missikate area, central Eastern Desert, Egypt

ABSTRACT

The present work is concerned with the fractionations of ²³⁸U, ²³⁰Th, ²²⁶Ra,²¹⁴Pb, ²¹⁴Bi, ²³⁵U, ²²⁸Ac, ²⁰⁸Tl and ⁴⁰K in sulphuric acid leaching and solvent extraction of uranium, in addition to, thiourea leaching of gold. The activity concentrations of the studied radionuclides indicate that uranium isotopes are highly leachable (89–90%) in sulphuric acid, while ²³⁰Th and ²⁰⁸Tl are leached with efficiency of about 76% and 71%, respectively. Less than 35% of ²²⁶Ra,²¹⁴Pb, ²¹⁴Bi and ²²⁸Ac are leached. In solvent extraction processes, uranium isotopes are selectively extracted and stripped. While ²⁰⁸Tl extraction was only 13%. Most of ²³⁰Th, ²²⁶Ra, ²¹⁴Pb and ⁴⁰K could not be extracted at such pH. The leachability of the studied radionuclides was significantly low using acidic thiourea. The dose rate and radium equivalent, in addition to the external and internal hazard indices values for the original sample and the uranium and gold tailings are higher than the recommended maximum values.

KEYWORDS:

• Isotopes fractionation
• gamma spectrometry
• leaching
• solvent extraction
• radiometric indices

Disclosure statement

No potential conflict of interest was reported by the author(s).